Files tab

Displays the files associated with the project. Drag and drop
files in the Files tab to
change the order in which the Intel® Quartus® Prime software processes them
during compilation.

The file type appear on the icon next to each file name listed
in the Device Design Files
and Software Files folders.
The Intel® Quartus® Prime software automatically sorts all files into the
Device Design Files, Software Files, and Other
Files folders, according to file extensions. The Intel® Quartus® Prime
software sorts design files for Intel FPGA IP cores according to the
Intel Quartus Prime IP File (.qip) Definition
they are associated with.